层理砂岩的双K断裂参数与尺寸效应试验研究  

Experimental study on the size effect of double K fractureparameters in stratified sandstone

作　　者：徐世烺[1] 韩明捷 王庆敏 刘福深 XU Shilang;HAN Mingjie;WANG Qingmin;LIU Fushen(Institute of Advanced Structures,Zhejiang University,Hangzhou 310058,China;Research Center of Coastal and Urban Geotechnical Engineering,Zhejiang University,Hangzhou 310058,China)

机构地区：[1]浙江大学高性能结构研究所,浙江杭州310058 [2]浙江大学滨海和城市岩土工程研究中心,浙江杭州310058

出　　处：《水利学报》2025年第3期287-296,共10页Journal of Hydraulic Engineering

基　　金：国家自然科学基金重点项目(5238003)。

摘　　要：砂岩作为一种代表性的沉积岩,在隧道开挖和边坡稳定等岩石力学工程问题中较为常见。同时,作为一种典型的准脆性材料,砂岩的断裂力学性质在工程应用中具有重要的意义。为了研究层理倾角和试样尺寸对砂岩双K断裂参数的影响,本文分别设置高度为10、20、40 mm,层理倾角为0°、30°、60°和90°的三点弯曲梁试样开展三点弯曲断裂试验。通过试验获得了完整的宏观响应曲线、断裂参数、破坏模式。结果表明:砂岩的断裂破坏过程可用双K断裂模型进行完整的描述,且层理倾角和试样高度对双K断裂参数均具有显著的影响;在试样高度一定时,随着层理倾角增大,试样峰值荷载、失稳断裂韧度、起裂断裂韧度均减小;而在层理倾角一定时,随着试样高度增加,试样峰值荷载和失稳断裂韧度增加,但起裂韧度变化不大,这进一步验证了起裂韧度是材料的固有属性。此外,试样的破坏模式也呈现明显的各向异性特征。随着层理倾角的增大,破坏模式逐渐表现出拉剪混合的破坏特点。Sandstone,as a representative sedimentary rock,is commonly encountered in engineering problems such as tunnel excavation and slope stability.As a typical quasi-brittle material,the fracture properties of sandstone are crucial mechanical characteristics in engineering applications.To investigate the influence of bedding plane orientation and specimen size on the double K fracture parameters of sandstone,this study conducted systematic three-point bending fracture tests using beam specimens with heights of 10,20 and 40 mm,and bedding angles of 0°,30°,60°and 90°,respectively.Complete macroscopic response curves,fracture parameters,and failure modes were obtained through the experiments,confirming that the fracture process of sandstone can be fully described using the double K fracture model.Both the dip angle of bedding and the specimen height significantly affect the double K fracture parameters:with a constant specimen height,the peak load,unstable fracture toughness,and initiation fracture toughness decrease as the bedding dip angle increases,while with constant bedding plane orientation,the peak load and unstable fracture toughness increase with specimen height,but the initiation toughness remains relatively unchanged,further verifying it as an inherent material property.Additionally,the failure modes of the specimens exhibit clear anisotropic characteristics based on bedding plane orientation,showing a mixed failure mode of tension and shear as the bedding dip angle increases.

关 键 词：砂岩 双K断裂模型 层理倾角 试样高度 破坏模式 

分 类 号：TU458[建筑科学—岩土工程]